Analysis of SARS-CoV-2 transmission in different settings, among cases and close contacts from the Tablighi cluster in Brunei Darussalam

Abstract

<jats:p>We report the transmission dynamics of SARS-CoV-2 across different settings from the initial COVID-19 cluster in Brunei, arisen from 19 attendees at the Malaysian Tablighi Jama′at gathering and resulted in 52 locally transmitted cases. Highest non-primary attack rates(ARs) were observed at a subsequent local religious gathering (14.8% [95%CI: 7.1,27.7]) and in the household (10.6% [95%CI: 7.3,15.1]. Household ARs of symptomatic cases were higher (14.4% [95%CI: 8.8,19.9]) than asymptomatic (4.4% [95%CI: 0.0,10.5]) or presymptomatic cases (6.1% [95%CI: 0.3,11.8]). Low ARs (&lt;1%) were observed for workplace and social settings. Our analysis highlights that SARS-CoV-2 transmission varies depending on environmental, behavioural and host factors. We identify ′red flags′ of potential super-spreading events, namely densely populated gatherings for prolonged periods in enclosed settings, presence of individuals with recent travel history, and group behaviours such as communal eating, sleeping and sharing of personal hygiene facilities. We propose differentiated testing strategies that account for transmission risk.</jats:p>

Susceptibility to SARS-CoV-2 Infection Among Children and Adolescents Compared With Adults

“…A total of 18 studies were contact-tracing studies (CTSs), 7,10,12,16-31 with 3 based in schools, [29][30][31] and 14 studies were population screening studies. 7, [32][33][34][35][36][37][38][39][40][41][42][43][44][45] Two were high quality, 33,35 22 were medium quality, 10,12,16,21,22,[24][25][26][27][29][30][31][32]34,36,38,[40][41][42][43][44][45] 7 were low quality, [17][18][19][20]23,28,39 and 1 was uncertain quality. 7,37…”

“…31 Lower secondary attack rates in children and adolescents compared with adults were reported by 11 studies: 5 from provinces of China, including Hunan, 10,22 Hubei, 16,18 and Beijing, 20 and 6 from other countries, including Taiwan, 17 Japan, 19 the US, 25,26 Israel, 21 and the Netherlands, 7,28 although confidence intervals were wide in some studies. No significant differences in secondary attack rates by age were reported in 3 studies from Guangdong province, China, 24 Brunei, 27 and the states of Tamil Nadu and Andhra Pradesh in India, 23 with 1 study from South Korea 12 reporting high secondary attack rates in those younger than 19 years. In 3 of these studies, 12,23,27 secondary attack rates in younger children were low compared with adults, but those among teenagers were as high as or higher than adults.…”

“…A total of 6 studies were from mainland China, 10,16,18,20,22,24 2 from the US, 25,26 and 1 each from Taiwan, 17 Japan, 19 South Korea, 12 Israel, 21 the Netherlands, 7,28 Brunei, 27 and India, 23 with 3 CTSs based in schools from Australia, 29 Ireland, 30 and Singapore. 31 Lower secondary attack rates in children and adolescents compared with adults were reported by 11 studies: 5 from provinces of China, including Hunan, 10,22 Hubei, 16,18 and Beijing, 20 and 6 from other countries, including Taiwan, 17 Japan, 19 the US, 25,26 Israel, 21 and the Netherlands, 7,28 although confidence intervals were wide in some studies.…”

Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: A living systematic review and meta-analysis

“…Since SARS-CoV-2 can be transmitted a few days before the onset of symptoms [124], presymptomatic transmission likely contributes substantially to overall SARS-CoV-2 epidemics. The analysis of secondary attack rates provides some evidence of lower infectiousness of people with asymptomatic than symptomatic infection (Fig 3) [36,65,66,90,111], but more studies are needed to quantify this association more precisely. If both the proportion and transmissibility of asymptomatic infection are relatively low, people with asymptomatic SARS-CoV-2 infection should account for a smaller proportion of overall transmission than presymptomatic individuals.…”

“…Five of the studies that conducted detailed contact investigations provided enough data to calculate a secondary attack rate according to the symptom status of the index cases (Fig 3) [ 36,65,66,90,111]. The summary risk ratio for asymptomatic compared with symptomatic was 0.35 (95% CI 0.1-1.27) and for presymptomatic compared with symptomatic people was 0.63 (95% CI 0.18-2.26) [66,90].…”